Long distance relationships

So there's this guy I've become close to recently and we've been talking every day for about a month with a group of people and just us talking every day for about a week. Everyone knows we like eachother but we haven't talked about it with eachother cuz we're both really awkward and shy. The problem is he lives in a different country and there's a 7 hour time difference between us. He is hopefully coming here for the summer and if he does were gonna give things a shot, but I'm worried about what to do when he leaves again because I'm not super experiences with relationships, especially not long distance, any advise?

Update:

He and I confessed to having feelings for eachother and now neither of us know what to do, we want to be together so badly but we're only in highschool so our lives aren't fully in our hands yet and it's so sad because where he is he goes into the military right after highschool and I want him to move here and stay and he wants to as well

Update:

He doesn't start conversations anymore and barely continues them and I don't know what to do now because I don't understand why he would stop talking to me right after he told me he liked me